The development of an electronic system includes designing the electronic system and verifying the proper operation of the electronic system. Simulation may be used to verify the proper operation of the electronic system. Simulation may provide excellent control of stimulus applied to the electronic system and ability to observe the resulting behavior of the electronic system. However, simulation may be slow, for example, simulation of one second of the operation of an electronic system may take may days, weeks, or even years of simulation time. Nevertheless, simulation is useful to discover and localize those defects in the electronic system that are detectable in a reasonable amount of simulation time.
Certain defects in the electronic system may be time-consuming to discover during simulation because the defects are not detectable in a reasonable amount of simulation time. A prototype of the electronic system may be used to discover and localize these defects. However, controlling the stimulus applied to the prototype of the electronic system may be challenging. In addition, expeditious localizing of a defect may require access to internal signals of the electronic system, and observing the behavior of these signals in the prototype may be time-consuming. For example, the design of a prototype environment may limit access to signals such that it may be simply impossible to access certain signals in the design under test.
An electronic design including a programmable logic device (PLD) has the advantage that the ability to observe internal signals of the electronic design in the PLD may be provided by certain tools, such as Chipscope available from Xilinx, Incorporated. A user of Chipscope may select a set of signals of a user design implemented on the PLD, and Chipscope provides access to these signals during operation of the electronic design. The access to internal signals in the PLD may expedite the localization of a defect in the electronic system.
Frequently, localization of a defect is an iterative process that traces from the symptom exhibiting the improper operation to the cause of the improper operation. For example, a particular signal may exhibit the improper operation for a defect. Examination of the logic generating this particular signal may indicate this logic is not the source of the defect, but that an input of this logic is the cause of the improper operation. Localizing a defect may require tracing back through many levels of logic to determine the defective logic that is the source of the improper operation. At each step of the iterative process, a different set of internal signals of the electronic design may need examination.
Each iteration examining a different set of signals may require a separate compilation step that translates the user design into a configuration for the PLD because Chipscope may include logic in the PLD to tap the particular signals being monitored. The separate compilation for each set of signals may be time-consuming, such that the localization of the defect is delayed.
The present invention may address one or more of the above issues.